Motion planning of human-like movements in the manipulation of flexible objects

The paper deals with modeling of human-like reaching movements in dynamic environments. A simple but not trivial example of reaching in a dynamic environment is the rest-to-rest manipulation of a multi-mass flexible object (underactuated system) with the elimination of residual vibrations. This a complex, sport-like movement task where the hand velocity profiles can be quite different from the classical bell shape and may feature multiple phases. First, we establish the Beta function as a model of unconstrained reaching movements and analyze it properties. Based on this analysis, we construct a model where the motion of the most distal link of the object is specified by the lowest order polynomial, which is not uncommon in the control literature. Our experimental results, however, do not support this model. To plan the motion of the system under consideration, we develop a minimum hand jerk model that takes into account the dynamics of the flexible object and show that it gives a satisfactory prediction of human movements.